1. Must the bearings be cleaned before installation?

The surface of the bearing is coated with anti-rust oil. You must clean it with clean gasoline or kerosene, and then apply it with clean high-quality or high-speed high-temperature grease. The effect of cleanliness on bearing life and vibration noise is very large. But we must remind you that the fully enclosed bearings do not need to be cleaned and refueled.

2. How to choose grease?

Lubrication has a very important influence on the operation and life of the bearing. Here is a brief introduction to the general principle of selecting grease. The grease is made of basic oil, thickener and additives. Grease performance of different types and different grades. The difference is very large, the allowable rotation limit is different, and it is important to pay attention when selecting. The performance of the grease is mainly determined by the base oil. Generally, the low viscosity base oil is suitable for low temperature, high speed and high viscosity for high temperature and high load. The thickener is also related to the lubricating properties, and the water resistance of the thickener determines the water resistance of the grease. In principle, the different greases of the brand cannot be mixed, and even the grease of the same thickener may have a bad influence on each other due to the different additives.

3. How to install and remove?

Do not directly hammer the bearing end face and the non-stress surface during installation. The bearing should be evenly stressed by the clamp, sleeve or other installation tools. Do not install by the rolling element transmission force. If the person on the installation surface is lubricated, it will make the installation smoother. If the interference is large, the bearing should be placed in mineral oil and heated to 80~90 °C and installed as soon as possible. The oil temperature should not be strictly controlled to exceed 100 °C to prevent the tempering effect from decreasing and affecting the dimensional recovery. When disassembling is difficult, it is recommended that you use the disassembly tool to pull outward while carefully pouring hot oil onto the inner ring. The heat will cause the inner ring of the bearing to expand, making it easier to fall off.

4. Is the radial clearance of the bearing as small as possible?

Not all bearings require a minimum working clearance and you must select the appropriate clearance depending on the conditions. In GB 4604-93, the radial clearance of rolling bearings is divided into five groups of 2 groups, 0 groups, 3 groups, 4 groups, and 5 groups. The clearance values are from small to large, and 0 is the standard clearance. The basic radial clearance group is suitable for general operating conditions, conventional temperature and common interference combination; bearings with high temperature, high speed, low noise, low friction and other special conditions should use large radial clearance; Small radial clearance should be used for precision spindles and bearings for machine tool spindles. In addition, there is no such thing as a separate type of bearing; finally, the working clearance after the bearing is installed is smaller than the original clearance before installation, because the bearing is subject to a certain load rotation, as well as the bearing fit and load. The amount of elastic deformation.

5. What are the common faults of rolling bearings?

1. The bearing temperature is too high: When the mechanism is running, the part where the bearing is installed is allowed to have a certain temperature. When the body of the mechanism is touched by hand, it should be normal to not feel hot, otherwise the bearing temperature is too high. The reasons for the excessive bearing temperature are: the quality of the lubricating oil does not meet the requirements or deteriorates, the viscosity of the lubricating oil is too high; the assembly of the mechanism is too tight; the bearing assembly is too tight; the bearing race rotates on the shaft or inside the casing; the load is too large; the bearing remains The frame or rolling body is broken and so on.

2. Bearing noise: The rolling bearing is allowed to have a slight running noise during operation. If the sound is too loud or there is abnormal noise or impact sound, it indicates that the bearing is faulty. The causes of noise generated by rolling bearings are more complicated. One is the wear of the inner and outer rings of the bearing. Due to this wear, the bearing and the housing, the bearing and the shaft are broken, resulting in the axis deviating from the correct position and generating an abnormal sound when the shaft is moving at a high speed. When the bearing is fatigued, the surface metal peeling off will also increase the radial clearance of the bearing to produce abnormal noise. In addition, insufficient bearing lubrication, dry friction, and bearing crushing can produce abnormal sounds. After the bearing wears loose, the cage is loose and damaged, and abnormal noise is also generated.

3, bearing wear: rolling bearing wear is a common equipment problem in the use of the shaft, mainly caused by the metal characteristics of the shaft. Although the metal has high hardness, it has poor retractability, poor impact resistance, and poor fatigue resistance, so it is likely to cause adhesive wear, abrasive wear, fatigue wear, fretting wear, and the like. Most of the shaft wear is not easy to detect. Only when there is high temperature, large amplitude of the machine, abnormal noise, etc., will it be noticed, but when people find out, most of the rolling shafts are worn out, causing the machine to stop.